Dunbar's Number

Metcalfe's Law: Why Second Place Is So Much Worse Than Second

Ten times the users gives roughly a hundred times the possible connections. The exact formula overstates things — the underlying point about compounding leads does not.

Dunbar's Number: The Limit Is Attention, Not Memory

You can recognise thousands of faces and actively maintain far fewer relationships. The famous figure of 150 is contested — the underlying constraint is not.